| No, you do not have to pay tax on the income that you received after 12/31/08. However, you should report this amount on your Schedule C and then take a deduction under a category that you can describe as "Amount not received in 2008."
If you are a cash basis taxpayer like most taxpayers, the IRS does not require you to report an item as income in 2008 if you have not "constructively received" this income in 2008. In your case, you have received this income in the subsequent tax year and hence it is not taxable in the tax year 2008! | 
